


Can't Mistake My Biology

by Indehed



Series: Biology [1]
Category: Hawaii Five-0 (2010)
Genre: Alpha Steve McGarrett, Alpha/Beta/Omega Dynamics, Alternate Universe - High School, Consensual Underage Sex, M/M, Omega Danny "Danno" Williams
Language: English
Status: Completed
Published: 2017-10-07
Updated: 2017-10-07
Packaged: 2019-01-10 10:00:13
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,290
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12296805
Author URL: https://archiveofourown.org/users/Indehed/pseuds/Indehed
Summary: It all starts when Steve shows up on Danny's doorstep unannounced and asks if he'll be his tutor for biology class...





	Can't Mistake My Biology

**Author's Note:**

> Unbeta'd. The fic amnesty continues. 
> 
> Tagged for consensual underage sex but I'm not sure...? Better safe than sorry. Steve and Danny are 16 here.

When the doorbell rang, Danny was close by, so he shouted up to his mother that he'd get it. He scowled as he opened the door, looking expectantly at the boy standing on the step.

"Hey," McGarrett said, puffing his chest up in confidence. 

They weren't friends. Steve was a jock, he was on the varsity football team and everyone figured he'd be the starting quarterback next year. He was one of the most popular kids in school. Danny was just the new kid and had enough going against him being an outsider before sub-gender even came into the equation.

"What are you doing here?" he asked suspiciously. He didn't even know McGarrett knew his name, let alone where he lived. 

"Mr Jenkin's biology class."

"What about it?"

Steve noticed his fidgeting hands and plunged them deep into his pockets instead. "I wondered if you'd be able to tutor me."

"Tutor you? I'm still trying to catch up after the move, I'm pretty sure there are plenty of other kids in the class better suited," he started to close the door, but Steve's hand stopped him. 

"But you're an omega, right?"

Danny cleared his throat. It wasn't something he'd been able to keep to himself for long. These things got out quickly in high school and the fact that the new kid was a male omega seemed to make a splash. "What of it?"

"That's what we're learning about in class," Steve explained only for Danny to roll his eyes. 

"I know. I'm in the class, too. I know what we're studying."

"So I figured if we're learning about the biology of omegas and **you're** an omega…" he tried to explain his logic. 

"What, and I'm some kind of expert? I'm learning, too. It's not like I want to go to my mom for that kind of stuff. Gross. If I asked you every detail about alphas, you think you'd be able to answer?" When Steve was quiet he continued. "I thought not. I'll see you in class, McGarrett."

"Wait," Steve tried one more time and Danny sighed at having to lean against the door again. 

"We did alphas last month before you got here. I'll catch you up on what Jenkins did with us if you help me get to grips with omegas," he offered, not even noticing the double entendre. It was then that Danny realized this might not be some stupid joke but he wasn't ready to believe McGarrett yet- there was definitely more to him showing up on Danny's doorstep unannounced than a desire to be tutored.

"I get the feeling if I don't say yes, you're going to keep hounding me," Danny narrowed his eyes. "Fine. I had to do the homework still anyway. Let me tell my mom and you can come up," he said and left the door open for Steve to come inside as he ran to the kitchen to find his mom who told him that was okay, and to remember she'd be going out to take his brother to his baseball practice and that his sister was out, too, so it would just be him in the house for a few hours and he better not burn the place down.

By the time he got back, Steve was looking around at the pictures on the walls intrigued, but he followed Danny up to his room and dropped his bag on the floor.

Danny sat on the bed and motioned for Steve to take the computer seat and to get his book out. 

They started with alphas and Steve let Danny copy his notes for what he'd missed. Steve wheeled closer to the bed and eventually sat back in the seat with his feet on the mattress. Danny didn't even notice at first, but recognized the behavior that they were just studying - of alphas getting comfortable in territory they considered their own. 

He swallowed, nervous, and hoped to God he was reading into things. It was stupid. No way would McGarrett be interested and no way was Danny returning any imagined interest anyway.

Steve finally let his feet fall to the floor again and leaned forward, elbows on his knees and holding his book out, pointing at the diagram of omega genitalia. "The girls' one makes sense but the guys'… so you have… both things?"

"Yes, we have the male penis with no balls, and we have the female vagina and womb."

"So if you're getting it on with someone, do you get like double pleasure if there's both bits or does only one work at a time."

"What?" Danny all but yelled and then pressed a hand to his mouth automatically trying to be quiet in case anyone was home yet. "What the hell kind of question is that?"

"A valid one," Steve said and then left his seat to sit beside Danny, books open in both their laps. "Wait, wait.. look at this bit," he said pointing at a paragraph. "It says that male omegas get pregnant more easily than females because they aren't limited to a heat cycle… because the main male gender dictates the urges for sex and the sub gender takes its cues from that." He looked up again at Danny. "So I guess if guys get turned on more easily, that's why male omegas can do it more, or something."

Steve was looking to Danny for answers, for confirmation, but he wasn't going to get it. They were sixteen and only just. They barely knew anything, either of them, no matter what they were. "Look, I don't know. I'm learning this stuff, too, I told you. I mean, they say male omegas are more likely to give birth to male omegas and yet we're the rarest sub-gender. So if your logic is correct, then that doesn't hold water. Male omegas would be pregnant all the damn time."

"Just because it's more likely, doesn't mean it helps boost the population, look at the charts," Steve showed Danny his book again. "It shows you the birth averages for all possible gender and sub gender pairs and it backs that up. Male omegas are rare because they are. No one knows why."

"Well there you go," Danny said. "I told you you'd learn more from the books than me, you didn't need my help with any of this."

"Why don't we try it out?"

"Try what out?"

"How it all works down there. I can help you," Steve put a hand to Danny's waist that was pushed off immediately. 

"No way!" Danny told him and rushed to lock the door - just in case. "That's ridiculous." He turned to lean on the door and realized that by locking it to protect himself from intrusion, he'd locked the two of them _in_ the room. Together. And by glancing at Steve he could see the alpha had noticed that, too.

"I'll show you mine," Steve offered, seeming quite calm in contrast to the boy Danny had greeted at the door an hour earlier.

"I don't need to see it. There's plenty of diagrams in the book. Besides, isn't this what the internet is for?"

"It's not the same. Come on. We can call it an experiment. Just for us though, I don't think Jenkins would allow it to be used in a paper for class…"

"You are insane. Why did I let you into my house?"

"Are you a virgin?" Steve asked, plowing on.

"What? That's none of your business."

"I mean, I'm not. And if you are, that's cool. I can understand why you might be worried."

"It's…" Danny flustered then forced himself to calm down and be cool. "Look, I am not your class experiment. I'm not a frog you can dissect-"

"Ew. No. Gross. I skipped class that day."

"My point is," Danny carried on. "You don't just come around someone's house and ask for sex like this!"

"I like you, Danny. I noticed you straight away when you arrived and I swear I could smell the omega on you from across the hall."

"That's not a thing."

"Feels like it to me," Steve shrugged. "I know it's not in the book. I kind of already read all the stuff about omegas. Even checked out a book from the library that said more about male ones because I needed to know if it meant something or not and there's nothing conclusive but I'm pretty sure I can still smell it."

"That'll be my deodorant. Or possibly my socks, I dunno." Danny kicked at the pair on the floor to move them under the bed and Steve reached out for his wrist and pulled him closer.

"It doesn't have to mean anything. And I've only had sex once before and with a female beta I'm friends with. Don't you want to know what it's like?"

"I'm a teenager, of course I do, but I can do that on my own," Danny pointed out, then realized what he'd implied and blushed. 

"It's different with a real person there," Steve told him. 

Danny wavered and Steve could tell he was wavering because he guided him down onto the bed and kept convincing him. "We're sixteen now. It's kind of expected that we'll do things like this. We're old enough. And I promise you, this is just between us. I'm not going to say anything at school. Not unless you want me to. You might not believe that because people know me as this alpha jock, but I like science and geography… I'm a straight A student in everything, even Home Ec. I'm not like the jocks you might have had at your old school."

Danny shook his head and looked up to the ceiling for guidance. All this talk of sex had begun to get him aroused anyway and Steve did smell good and look good. He couldn't deny he'd caught himself staring a few times and had to reprimand himself over the fact that Steve was probably riddled with character flaws and the six-pack abs wouldn't overrule that.

He looked down to see Steve's hand covering his crotch, thumb lightly caressing the material of his pants. He caved. "Fine. Okay, but just this once."

Steve helped him out of his pants and he got nervous before pushing his underwear down, unsure if what he looked like down there was appealing. With a little prodding he shoved them down, figuring he had to do this eventually with someone and it might as well be now and with Steve, so he ignored the little warning voice in the back of his head that told him he wasn't ready.

"Wow, okay," Steve said at the sight of Danny's dick. He pushed a hand down against where he was getting hard under his own jeans and slid to the floor. "Why don't you lie back and put your feet on the bed."

"What are going to do?" Danny asked, but did as Steve suggested. 

"Well, I want to take a look," he said and Danny strained his head up to watch Steve's reaction. His index finger then stroked down from under Danny's dick and over both holes - the first of which Danny knew was getting wet already. 

"That's not looking," he said and huffed a nervous laugh. 

"Sorry, I moved onto touching," Steve said. "I can smell you down here. That's the slick, right?"

Steve's thumb rubbed over the wet hole and the nub of his clit and it made Danny mumble a low _'fuck'_. 

"Is that good?" he asked Danny who breathed out a 'yeah' and Steve pressed his thumb against him again, harder, and rubbed between the clit and pussy. He shifted back to his index finger and, with Danny getting seriously wet, Steve pushed his finger inside. 

Danny held his breath - Steve had done it so quickly and all the way in. He lifted his head again and looked down his body to see the smug grin on Steve's face as he began to move the finger in and out of Danny.

"This is really easy," he said. "You're really wet and your dick's getting harder too. It's like the book says, both happen at once. What does it feel like?"

"I don't know. What does it feel like for you getting aroused?" Danny shot back. 

Steve ignored the question. "Have you done this to yourself or have you only ever jacked off your dick?"

It was said almost innocently, or like the kind of conversation you'd have over the lunch table and Danny felt embarrassment that clearly Steve didn't. Maybe that was the perk of being an alpha -when it came to sex you just got on with it. And maybe there was an element of taking what you wanted. Danny should be mad about that, mad at himself for giving in and yet here he was not stopping anything. He didn't even want to. 

When Steve's finger stopped pumping in and out of him he felt the loss. "No, don't stop, keep going," he told him. 

"Relax, I will in a second. My jeans are feeling uncomfortable, I'm just going to get my dick out. It's getting hard at the sight of all this slick. Besides, it's only fair that I get half naked, too."

A moment later, Steve's finger returned and Danny relaxed back comfortably onto the bed and closed his eyes. The finger moved slower than he wanted. He was used to being able to dictate everything he needed for himself but with Steve, he had to tell him. "More," he said. "Faster."

"Wait," Steve said. "I'm going to try something," and then when he pushed back in it was fuller, there was more. Another finger. He was pushing two in and out of Danny and it made him keen with need. He was getting worked up, so worked up, he needed to be filled up. Fuck, he knew this feeling and he didn't want Steve to see him get so needy but it felt so good and Steve could give him what he needed in new ways. Before he'd only been able to use fingers - never brave enough to buy something to help. Steve's dick would be bigger than three fingers and oh shit, the thought of it made his brain want to go into omega meltdown. 

When Steve pulled completely away again, Danny had to stifle his dissatisfied moan. But Steve began to jack Danny's dick, giving his other parts attention and it felt good, too, but what he really wanted was both at once. 

"Steve, fuck… I want…"

"You want me to fuck you? I will, Danny, if that's what you want. This is amazing, seeing you like this because of my hands…"

"Come on," Danny motioned for him to keep going, to do more. He was giving permission.

Steve stumbled to his feet and began raking in his bag, lifting the small packet with success, he tore it open and quickly pushed the condom on. He shoved his jeans to his ankles and stood with his knees braced to the bed. He pulled Danny's body down a little further, closer. 

"You want me to go for it or do you need more stretching?"

"Do it, I'm slick and empty, I need it," Danny all but begged of him and with a smug, satisfied smile, Steve lined his dick up and began to push it inside Danny. It was easy for a bit until there was a sharp sting of pain and he had to stop to allow Danny to get used to the feeling. It was his first time, of course it was going to hurt when he got something bigger inside him than ever before. Steve slowed, but kept going and constantly murmured to Danny to relax and to breathe and not to worry, it would feel better in a few moments. 

Once he was fully seated inside, he wriggled a little on top of Danny, to let him feel how it was. "Holy shit, you're tighter than I've felt before," Steve whispered by his ear. 

"It's still sore," Danny said, feeling his arousal wane as he worried about it. 

"Maybe if I touch your dick, that'll help. Like it'll distract you or something," Steve suggested then lifted up onto an elbow and got his hand between them. He inadvertently grabbed onto Danny's dick tighter than either expected and had to apologize before loosening his grip and slowly jacking him off.

After a couple of tugs he began to move his hips in the same rhythm. Danny wasn't sure if he was ready or not. The little sparks of pain remained no matter what, he just felt like his dick's enjoyment was trying to distract him. Which was what Steve thought of, that much was true. But Danny wanted to know that he could enjoy sex without pain, without clenching up. It was supposed to get easier, right? Or was that once he'd done it a few times and not just easier as he got through the first time?

He knew what he liked, though. He'd touched himself enough. He was a teenager, he'd seen the magazines and he'd looked at those old library books and yeah, there was the internet (when he knew he could be careful and delete his history) so he'd figured out a few things. 

He reached a hand between them, fumbling past Steve's and his fingers probed against his stretched pussy and the way Steve's rubber-covered dick pushed in and out of him. He looked up at Steve to see he was almost blissed out. As much as the alpha was trying to help Danny, he was getting caught up in his own pleasure. Danny rubbed his fingers over his clit, flicking his fingers over the sensitive nub and it helped. He was starting to get into the flow of it, feeling his own arousal take hold then suddenly-

"Fuck, fuckfuckfuck, Dann-oooooh," Steve halted, a mixture of surprise, fear and release as he came inside Danny before looking down between them. 

"What's with the Dann-ooh-?" Danny asked, mimicking Steve.

"Fuck, hold on. Shit. I think-"

"What?" Danny asked, annoyed that Steve had come and he was still needing to.

"I think I knotted."

"You _**think?!**_ " Danny's voice went up an octave. If Steve had knotted they could be attached together for ages and his mom would be home soon. Shit, he felt the arousal drain from his body again.

They both fumbled between themselves to where Steve was inside Danny. "It's really tight," Steve said, grimacing a little. He grabbed Danny's wrist where he was more frantically exploring and pushed him to the bed before doing the same with Danny's other hand. With both braced to the bed, one either side of Danny's head, Steve gave a small thrust into him again as he lay flatter on top of the omega and looked down on him.

They lay still, panting. 

There was awe in the way Steve looked at Danny. Curiosity. And something happy though Danny wanted to say smug. Satisfied. Steve rolled his hips a little and it made Danny gasp and Steve beamed down at him. "Hey," he said, trying for cool.

"Are you really knotted?" Danny asked, apprehension still in his quit words. 

"I think it's okay," Steve replied then laughed a little. "Should have seen your face though!"

"You idiot!" Danny tried to get his hand free to shove at Steve but the alpha had strength and the better position over him and all he could do was give a token struggle. "Take it out of me," he ordered. 

"But you didn't come yet."

"You've literally scared the arousal back out of me," Danny grumbled. 

Steve relented, seeing that Danny was a bit upset. He pulled out and his eyes widened at the jizz inside the condom and he remarked at how much there was considering how fast Danny's tight pussy had made him come. 

Danny was still touching himself, more out of concern to make sure his body was okay than anything else. Then he began to wonder as Steve pulled his pants up. "Did you come over wanting to get laid? New guy might be easy? Is that it?"

"No," Steve turned back to him. "No, man, no. I came over because I wanted to spend some time with you. I mean the tutoring thing was an excuse, I admit it. I liked you when you got here but you always stay away from people at school. I thought maybe one on one we'd have a better chance to get to know one another. The sex was just a bonus. Hey," Steve slid to his knee again between Danny's legs where he was still sitting on the bed, bottom half still naked and on show. "Let me touch you again. I want to see you when you come."

"Steve, really, the knotting scare just-"

"I know you were still feeling a bit sore. I guess that's what it's like first time for omegas. I mean you were really tight, that's what made me come so quick. I'd kinda like a chance to see if I can do something you really enjoy."

"I dunno. The time-"

"I can do this," Steve told him then stood and positioned himself on the bed so he was sitting behind Danny. He pulled the omega so that his back was flush to Steve's chest the he reached around and down. He started by pulling on Danny's half-hard dick. "This angle, it's kinda like doing it to myself and at least this part of our anatomy is similar."

"Except I can't make anyone pregnant with what comes out of mine when I orgasm," Danny reminded the alpha. 

"Bet it's pretty though. When you come," Steve said by Danny's ear. While his right hand continued to pump Danny's cock, his left slipped under, a finger rubbing against his clit again. The finger fluttered over the nub, rubbing fast to give him more stimulation. 

Danny's eyes closed and his head fell back to Steve's shoulder, butt lifting from the bed as he sought the touch. The build was fast and Steve was mumbling crap in his ear about how good he looked and to keep going, let it out. Just as he felt his body tensing up Steve managed to slip a finger inside Danny and furiously thrust in and out while stroking his clit and his right hand pumped his dick as fast as it could and then he was coming. 

He felt the slick dribbling between his legs and watched the spurts of it come out of his dick before he collapsed back into Steve, boneless. 

"Wow," Steve breathed out as his fingers trailed through the sticky mess. "So that's what it's like for an omega. I could feel it on my finger."

"I came fast," Danny said, unsure if that was an apology or something he was proud of. 

"Me too," Steve shrugged a little, his response pretty similar in being unsure whether to brag or not about it. 

"Man, I need to clean all this up. And open a window," Danny said, lifting from the bed so quickly that Steve's arms halted in mid air as if still holding onto him. He grabbed a bunch of tissues and wiped between his legs and over his stomach before he got his pants back on. As he zipped up the fly he moved to the window and flung it open, hugely aware of the funk of sex and heat hanging in the room. 

When he turned around again Steve was right there and he bumped into the boy's chest. After a moment of awkward pause, Steve leaned down and pressed his lips to Danny's; both boys realizing this was the first kiss they were sharing despite them already having… well, done what they'd done. 

Steve put an arm around Danny's waist. "At school, you're gonna talk to me now, right?"

"Uhm, we don't exactly hang in the same kind of crowds," Danny reminded him. 

"Cliques are stupid. I want to spend time with you, Danny. Besides, if we're starting something it makes sense to be seen together."

"Starting what?"

"A relationship."

"I've barely said two words to you before today and you think we're what, 'going steady' now?"

"We just had sex," Steve pointed out. 

"Oh," was all Danny could answer with. 

"Oh," Steve echoed in part mimic before he kissed Danny's stunned lips again. "Listen, I gotta go. Dad said I had to be home by dinner. I'll see you tomorrow," he moved away and began to gather his things. 

"Yeah, okay," Danny told him, unsure what was going on, what had happened, he'd just had sex, what the fuck. It hit him like a hammer. 

"I think I'm going to ace the biology quiz," Steve said with a wink as he stood again, backpack slung over his shoulder. He reached in, a hand behind Danny's neck and he pulled in to kiss his forehead before heading for the door and unlocking it, disappearing out the room to see himself out. 

Danny sat on his bed with a thump then screwed up his nose as he realized he'd just sat in a wet patch of his own slick. He then picked up the condom Steve had forgotten about. With careful fingers he tied a knot in it, wrapped a bunch of tissues around it, stuffed it in an old plastic bag that he then also tied a knot in, then put it in the middle of the waste paper basket under a bunch of crumpled up paper and candy wrappers.

Holy crap that all just happened.


End file.
